1. Field of the Invention
This invention relates to a seat with an adjusting mechanism for adjusting the height of a head rest.
2. Description of the Related Art
A conventional seat with an adjusting mechanism for adjusting the height of a head rest is disclosed in Japanese Utility Model No. 7(1995)-34761. This seat comprises a seat cushion, a seat back rotatably connected to the seat cushion, a head rest disposed on the seat back so as to be able to move in the vertical direction, lower rails attached to the vehicle floor, upper rails movably disposed on the lower rails and which supports the seat cushion, a seat slide mechanism for sliding the upper rails in the longitudinal direction relative to the lower rails, a raising and lowering mechanism for raising and lowering the head rest relative to the seat back, and an interlock mechanism for interlocking the seat slide mechanism and the raising and lowering mechanism.
In accordance with the prior art, the interlock mechanism for interlocking the seat slide mechanism and the raising and lowering mechanism includes a first connecting member formed with an elastic member for forcing the head rest in the upper direction and a wire which is engaged with the head rest and extending in the lower direction. This interlock mechanism further includes a first pulley connected to one end of the wire of the first connecting member for winding the wire, a first gear rotating with the first pulley, a second gear meshed with the first gear so as to reduce the rotational speed, a second pulley rotating with the second gear, a second connecting member including a wire of which one end is connected to the second pulley for winding the wire and the other end is connected to the vehicle floor.
In accordance with this construction, when the seat cushion slides in the forward direction, the wire of the second connecting member is pulled in the downward direction so as to lower the head rest against the elastic force of the elastic member through the second pulley, the second gear, the first gear, the first pulley and the wire of the first connecting member. When the seat cushion slides in the rearward direction, the wire of the second connecting member slackens and the head rest rises by the elastic force of the elastic member.